1 Division of Endodontics and Periodontology, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan.
2 Division of Endodontics and Periodontology, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.
3 Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan.
4 Division of Endodontics and Periodontology, Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan. Electronic address: ycho5@vghtpe.gov.tw.